Blue tint / streaks on Sony PVM
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buttersoft
- Posts: 377
- Joined: Sun Jul 24, 2016 7:49 am
Re: Blue tint / streaks on Sony PVM
Which model PVM? What happens when you turn down the blue bias? (or turn down brightness and turn up the red bias and green bias).
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buttersoft
- Posts: 377
- Joined: Sun Jul 24, 2016 7:49 am
Re: Blue tint / streaks on Sony PVM
Down those holes for bias and gain are potentiometers. You need either a thin phillips head or a thin flat head screwdriver - shine a keyring torch down the hole to have a look. A set of jeweller's screwdrivers would do the trick.
Bias is for black levels, do this first - you set brightness and then adjust the 3 colours. Get right up close to the screen and have a look at the effect. On a tube in good condition, there should be no glow from the phosphors for black. Hopefully playing around here can remove the diagonal blue lines.
Gain is for white levels. See if you can input a white screen via 240p test suite on the wii or something, then adjust the 3 gain levels so it's pure white.
The diagonal lines are probably retrace lines. As the beam moves back into position they show up when the brightness is too high, hopefully just blue brightness here. If setting the blue bias down doesn't work, try lowering overall brightness and dialling up the red bias and green bias. If this still doesn't work, the next step is to open the set and dial down the "Screen" adjustment. This can act like a master brightness control in some circumstances. I believe it's on the flyback for this PVM, but the service manual should tell you. I'll see if I can check that out.
If you've never opened a set before, do it on a flat surface like a big table with lots of space around, and make sure you have a torch so you can read markings. Have a good look around while the set is off, and don't stick your fingers in our touch anything. While the set is off the only dangerous bit if you insist on playing with it is the anode button (around the rubber suction cup on the back of the tube) and the thick lead coming from it. That lead goes to the flyback. Figure out which dial on the flyback is the sceeen adjustment - it will be labelled just that. The adjustment needs to be made while the set is running, but it's the only thing you'll need to touch. Wear work gloves, use a screwdriver. Keep your other hand in your pocket, and don't have any stray cords or unneeded electrical stuff around. Making this single adjustment is not hard, or dangerous if you have a little common sense, but there's no harm in taking your time. It will turn the overall brightness down, or up, and then you go back to step one and do the bias again.
Apologies if you knew most of this already!
Bias is for black levels, do this first - you set brightness and then adjust the 3 colours. Get right up close to the screen and have a look at the effect. On a tube in good condition, there should be no glow from the phosphors for black. Hopefully playing around here can remove the diagonal blue lines.
Gain is for white levels. See if you can input a white screen via 240p test suite on the wii or something, then adjust the 3 gain levels so it's pure white.
The diagonal lines are probably retrace lines. As the beam moves back into position they show up when the brightness is too high, hopefully just blue brightness here. If setting the blue bias down doesn't work, try lowering overall brightness and dialling up the red bias and green bias. If this still doesn't work, the next step is to open the set and dial down the "Screen" adjustment. This can act like a master brightness control in some circumstances. I believe it's on the flyback for this PVM, but the service manual should tell you. I'll see if I can check that out.
If you've never opened a set before, do it on a flat surface like a big table with lots of space around, and make sure you have a torch so you can read markings. Have a good look around while the set is off, and don't stick your fingers in our touch anything. While the set is off the only dangerous bit if you insist on playing with it is the anode button (around the rubber suction cup on the back of the tube) and the thick lead coming from it. That lead goes to the flyback. Figure out which dial on the flyback is the sceeen adjustment - it will be labelled just that. The adjustment needs to be made while the set is running, but it's the only thing you'll need to touch. Wear work gloves, use a screwdriver. Keep your other hand in your pocket, and don't have any stray cords or unneeded electrical stuff around. Making this single adjustment is not hard, or dangerous if you have a little common sense, but there's no harm in taking your time. It will turn the overall brightness down, or up, and then you go back to step one and do the bias again.
Apologies if you knew most of this already!